Solid Ink Stick Delivery System with Static Constraints, Strategic Barriers and Breakage Control

ABSTRACT

An ink delivery system of a phase change ink imaging device more effectively guides properly configured solid ink sticks from a first end of a feed chute to a melting device at a second end of the feed chute. The feed chute may include a sensor to detect coded sensor features on the properly configured solid ink sticks traveling along the feed chute and an obstructor configured to block improperly configured solid ink sticks inserted into the first end of the feed chute.

CLAIM OF PRIORITY

This application is a divisional application of and claims priority tocommonly-assigned U.S. patent application Ser. No. 11/900,352, which isentitled “Solid Ink Stick Delivery System With Static Constraints,Strategic Barriers and Breakage Controls” (attorney docket no.1776-0175) to Jones et al., which was filed on Sep. 11, 2007 and whichissues as U.S. Pat. No. 7,909,445 on Mar. 22, 2011.

CROSS-REFERENCE TO RELATED APPLICATIONS

Reference is made to commonly-assigned U.S. patent application Ser. No.11/900,419, which is entitled “Solid Ink Stick with Anti Jam Edge Bevel”(attorney docket no. 1776-0176) to Mattern et al., which was filed onSep. 11, 2007, and which issued as U.S. Pat. No. 7,824,027 on Nov. 2,2010, the entire disclosure of which is expressly incorporated byreference herein in its entirety.

TECHNICAL FIELD

This disclosure relates generally to phase change ink jet printers, thesolid ink sticks used in such ink jet printers, and the load and feedapparatus for feeding the solid ink sticks within such ink jet printers.

BACKGROUND

Solid ink or phase change ink printers conventionally receive ink in asolid form, either as pellets or as ink sticks. The solid ink pellets orink sticks are typically inserted through an insertion opening of an inkloader for the printer, and the ink sticks are pushed or slid along thefeed channel by a feed mechanism and/or gravity toward a heater plate inthe heater assembly. The heater plate melts the solid ink impinging onthe plate into a liquid that is delivered to a print head for jettingonto a recording medium.

One problem faced in solid ink technology is differentiation andidentification of ink sticks to ensure the correct loading andcompatibility of an ink stick with the imaging device in which it isused. The wrong color of ink stick in a feed channel, ink sticksintended for different solid ink printers, use of non-qualified ink,etc. may impact image quality or even damage the solid ink imagingdevice. Provisions have been made to ensure that an ink stick iscorrectly loaded into the intended feed channel and to ensure that theink stick is compatible with that printer. For example, the correctloading of ink sticks has been accomplished by incorporating keying,alignment and orientation features into the exterior surface of an inkstick. These features are protuberances or indentations that are locatedin different positions on an ink stick. Corresponding keys or guideelements on the perimeters of the openings through which the ink sticksare inserted or fed exclude ink sticks which do not have the appropriateperimeter key elements while ensuring that the ink stick is properlyaligned and oriented in the feed channel. Another method that has beenimplemented to aid in the identification of an ink stick by a printercontrol system is the incorporation of encoding features into theexterior surface of ink sticks that interact with sensors in the inkdelivery system. Ink stick data may be encoded into these features byconfiguring the features to interact with one or more sensors in an inkloader to generate a signal or coded pattern of signals that correspondsto information specific to the ink stick.

Emerging phase change ink jet technologies have reduced the time forgenerating solid ink images, and, consequently, have a high inkconsumption rate. As a consequence, larger capacity solid ink deliverysystems are needed. To increase the amount of ink that may be loaded inan ink delivery system, solid ink delivery systems have been providedwith non-linear feed channels. Non-linear feed channels may include anynumber of linear and curved sections that can feed and guide ink sticksfrom an insertion end the ink delivery system to an ink melting assemblyof the ink delivery system. The feed channels are typically at leastpartially enclosed in order to retain, orient, and guide the ink sticksalong the feed path and to prevent ink debris in one channel fromcontaminating the other channels or the interior of the imaging device.

The increased capacity of solid ink delivery systems having non-linearfeed channels has prompted the development and use of ink sticks havinga larger length to width aspect ratio. The use of “longer” ink stickslessens the frequency at which the solid ink in the ink delivery systemhas to be replenished. Larger ink sticks, however, may have greaterfabrication stresses than smaller ink sticks due to the nature of theslow cooling rate of the ink and the difference in post formingshrinkage between the outer and inner ink volumes. Therefore, larger inksticks may be more prone to breaking into multiple smaller pieces whenmishandled. Broken ink sticks may not feed reliably resulting inundesirable skewing and jamming of the ink stick pieces in the feedchannels.

In addition, increasing the size of the ink sticks may result in acorresponding increase in the tolerances for construction of thecorresponding ink delivery system. These increased tolerances may leadto larger clearances around the keying, guiding, alignment, and/ororientation features as well as sensors in the solid ink deliverysystem. These enlarged clearances may allow undesirable skewing andjamming of the ink sticks in some ink feed channels as well as incorrectpositioning of ink stick encoding features with respect to thecorresponding sensors. Moreover, the increased clearances may allow theuncontrolled passage of smaller ink sticks and/or pieces of broken inksticks to the melt assembly of the ink delivery system. If the smallerink sticks or ink stick pieces are incompatible with the phase changeink jet printer in which they are being used, considerable errors andmalfunctions may result.

SUMMARY

In order to address the needs associated with the previously knownsystems, a system for an ink loader is provided that improves feedcontrol of ink sticks by optimizing the position of ink sticks withrespect to ink sensing elements in an ink loader. The system comprises afeed chute having an insertion end and a melt end. An ink sticktransport is configured to move at least one ink stick between theinsertion end and the melt end of the feed chute. At least one sensor ispositioned in the feed chute for detecting a coded sensor feature of theat least one ink stick moving along the feed chute between the insertionend and melt end. The system includes at least one nudger positioned inthe feed chute that is configured to influence a position of the atleast one ink stick moving along the feed chute so that the coded sensorfeature of the at least one ink stick is in a sensing position withrespect to the at least one sensor.

In another embodiment, a method of feeding ink sticks in an ink deliverysystem of a phase change ink imaging device comprises receiving at leastone ink stick in a feed chute at an insertion end of an ink deliverysystem of a phase change ink imaging device, the at least one ink stickincluding a coded sensor feature for actuating at least one sensor inthe feed chute. The at least one ink stick is moved toward a melt end ofthe feed chute. The moving ink sticks are nudged so that the codedsensor feature of the at least one ink stick is in a sensing positionwith respect to the at least one sensor in the feed chute. The codedsensor feature of the at least one ink stick is then detected with theat least one sensor.

In yet another embodiment, a system is provided that enhances feedcontrol by allowing appropriately shaped and sized ink forms to be fedalong a feed chute while impeding the passage of incorrect, out of date,mismatched ink shapes as well as broken ink stick sections. The inkdelivery system comprises a feed chute having an insertion end and amelt end, and an ink stick transport for moving at least one ink stickbetween the insertion end and the melt end of the feed chute. Aninsertion opening is positioned at the insertion end of the feed chutethat is sized to receive ink sticks having an insertion length. At leastone pair of nudgers in the feed chute is beneath an area nearer theleading end of the insertion opening. An obstructor is positioned behindthe at least one pair of nudgers. The at least one pair of nudgers isconfigured to position at least the leading end of ink sticks having aninsertion length beyond the obstructor as the ink sticks having theinsertion length are moved toward the melt end of the feed chute, and toallow ink sticks having a length less than the insertion length to beimpeded from movement toward the melt end by the obstructor.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of a phase change ink imaging device.

FIG. 2 is an enlarged partial top perspective view of an embodiment ofan incomplete phase change ink imaging device with an ink loader.

FIG. 3 is a perspective view of one embodiment of a solid ink stick.

FIG. 4 is a top view of a keyed opening of the ink delivery system.

FIG. 5 is a side view of an embodiment of an ink stick that includesclearance edges.

FIG. 6 is a side view of a feed channel in which a pair of ink stickshaving clearance edges are shown being fed.

FIG. 7 is a top view of a portion of an embodiment of a feed channelthat includes strategic constraints.

FIG. 8 is a side view of an embodiment of an ink stick that includes acoded sensor feature.

FIG. 9 is a top view of an embodiment of a feed channel that includes asensor system for reading a coded sensor feature of the ink stick ofFIG. 8 and strategic constraints for controlling positioning of the inkstick in relation to the sensor system.

FIG. 10 is a top view of an insertion area of an embodiment of a feedchannel that includes strategic barriers and the interaction of thestrategic barrier and a correctly configured ink stick.

FIG. 11 is another top view of the insertion area of the embodiment ofthe feed channel of FIG. 10 that includes strategic barriers and theinteraction of the strategic barrier and an incorrectly configured inkstick.

FIG. 12 is a front view of an embodiment of a feed channel insertionarea that includes static constraints and strategic barriers.

FIG. 13 is a top view of the embodiment of the feed channel of FIG. 12.

FIG. 14 is a top view of an embodiment of ink stick that includesbreakage control features.

FIG. 15 is a top view of the insertion area of the embodiment of thefeed channel of FIG. 12 that shows the interaction of the staticconstraints and strategic barriers with an ink stick fractured inaccordance with the breakage control feature.

FIG. 16 is a side view of a feed channel that includes a combinationbarrier/constraint in the form a spring loaded roller.

FIG. 17 is another side of the feed channel of FIG. 16.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

For a general understanding of the present embodiments, reference ismade to the drawings. In the drawings, like reference numerals have beenused throughout to designate like elements. As used herein, the term“printer” refers, for example, to reproduction devices in general, suchas printers, facsimile machines, copiers, and related multi-functionproducts, and the term “print job” refers, for example, to informationincluding the electronic item or items to be reproduced. References toink delivery or transfer from an ink cartridge or housing to a printheadare intended to encompass the range of melters, intermediateconnections, tubes, manifolds and/or other components and/or functionsthat may be involved in a printing system but are not immediatelysignificant to the present invention.

Referring now to FIG. 1, there is illustrated a block diagram of anembodiment of a phase change ink imaging device 10. The imaging device10 has an ink supply 14 which receives and stages solid ink sticks. Anink melt unit 18 heats the ink stick above its melting point to produceliquefied ink. The melted ink is supplied to a printhead assembly 20 bygravity, pump action, or both. The imaging device 10 may be a directprinting device or an offset printing device. In a direct printingdevice, the ink may be emitted by the print head 20 directly onto thesurface of a recording medium.

The embodiment of FIG. 1 shows an indirect, or offset, printing device.In offset printers, the ink is emitted onto a transfer surface 28 thatis shown in the form of a drum, but could be in the form of a supportedendless belt. To facilitate the image transfer process, a pressureroller 30 presses the media 34 against the ink on the drum 28 totransfer the ink from the drum 28 to the media 34.

Operation and control of the various subsystems, components andfunctions of the machine or printer 10 are performed with the aid of acontroller 38. The controller 38, for example, may be a micro-controllerhaving a central processor unit (CPU), electronic storage, and a displayor user interface (UI). The controller reads, captures, prepares andmanages the image data flow between image sources 40, such as a scanneror computer, and imaging systems, such as the printhead assembly 20. Thecontroller 38 is the main multi-tasking processor for operating andcontrolling all of the other machine subsystems and functions, includingthe machine's printing operations, and, thus, includes the necessaryhardware, software, etc. for controlling these various systems.

Referring now to FIG. 2, the device 10 includes a frame 44 to which theoperating systems and components are directly or indirectly mounted. Asolid ink delivery system 48 advances ink sticks from loading station 50to a melting station 54. The melting station 54 is configured to meltthe solid ink sticks and supply the liquid ink to a printhead system(not shown). All forms of solid ink are referred to as ink sticks orsimply ink or sticks. The ink delivery system 48 includes a plurality ofchannels, or chutes, 58. A separate channel 58 is utilized for each ofthe four colors: namely cyan, magenta, black and yellow.

The loading station includes keyed openings 60. Each keyed opening 60limits access to one of the individual feed channels 58 of the inkdelivery system. The keyed openings 60 are configured to accept onlythose ink sticks having key elements that comport with the keystructures of the openings 60. Thus, the keyed openings 60 help limitthe ink sticks inserted into a channel to a particular configurationsuch as color, ink formulation, etc.

To better utilize the space within the imaging device 10, the feedchannels 58 may have any suitable path for delivering ink sticks fromthe loading station 50 to the melt station 54. For example, the feedchannels 58 may have linear and curved sections as needed to providespace for other components and to still deliver ink sticks from theloading station 50 to the melting station 54. An arcuate portion of thefeed path may be short or may be a substantial portion of the pathlength. The full length of the chute may be arcuate and may consist ofdifferent or variable radii. A linear portion of the feed path maylikewise be short or a substantial portion of the path length. All or atleast a portion of the feed channels are enclosed by a confining wall.The confining wall aids in guiding, orienting, and/or aligning inksticks as they travel from the loading station to the melting station,and prevents ink debris from escaping the respective feed channels tocontaminate the other feed channels and the interior of the imagingdevice.

The depicted solid ink delivery system 48 includes a drive member (notshown) for moving one or more ink sticks 68 along the feed path in therespective feed channel 58. A separate drive member may be provided foreach respective feed channel. The feed channel 58 for each ink colorretains and guides ink so that the ink progresses along a desired feedpath. The drive member, if utilized, may have any suitable size andshape. The drive member may be used to transport the ink over all or aportion of the feed path and may provide support or guidance to the inkand may be the primary ink guide over all or a portion of the feed path.As explained in more detail below, feed channels may include staticconstraints and/or strategic barriers to ensure reliable feeding ofproperly configured ink sticks and to prevent or impede the passage ofbroken or improperly configured ink sticks and may employ gravity as afeed force or influence.

An exemplary solid ink stick 100 for use in the ink delivery system 20is illustrated in FIG. 3. The ink stick has a bottom surface 134 and atop surface 138. The particular bottom surface 134 and top surface 138illustrated are substantially parallel to one another, although they cantake on other contours and relative relationships. Moreover, thesurfaces of the ink stick body need not be flat, nor need they beparallel or perpendicular one another. The ink stick body also has aplurality of side extremities, such as lateral side surfaces 140, 144and end surfaces 148, 150. The side surfaces 140 and 144 aresubstantially parallel to one another, and are substantiallyperpendicular to the top and bottom surfaces 134, 138. The end surfaces148, 150 are also basically substantially parallel to one another, andsubstantially perpendicular to the top and bottom surfaces, and to thelateral side surfaces. One of the end surfaces 148 is a leading endsurface, and the other end surface 150 is a trailing end surface. Theleading end 148 and the side surfaces 140, top surface 134 and bottomsurface 138 meet to define a plurality of leading edges 160, 164, 168,170, and the trailing end 150 and the side surfaces 140, top surface 134and bottom surface 138 meet to define a plurality of trailing edges 174,178, 180, 184.

Ink sticks may include a number of features that aid in correct loading,guidance and support of the ink stick when used. These features maycomprise protrusions and/or indentations that are located in differentpositions on an ink stick for interacting with key elements, guides,supports, sensors, etc. which are located in complementary positions inthe ink loader. For example, FIG. 3 shows an embodiment of an ink stickthat includes insertion keying features 154. The stick keying featuresinteract with the keyed openings 60 of the loading station 50 to admitor block insertion of the ink sticks through the insertion opening ofthe solid ink delivery system 48. In the ink stick embodiment of FIG. 3,the key element 154 is a vertical recess or notch formed in side surface140 of the ink stick body. The corresponding complementary key 158 onthe perimeter of the keyed opening 60 is a complementary protrusion 158into the opening 60 (See FIG. 4). Any number or shape of key featuresmay be employed in any suitable position on the ink stick.

Due to the high ink consumption rates that are possible with phasechange ink imaging devices, the ink stick 100 may have an aspect ratioin which the longitudinal length of the ink stick body between theleading end 148 and the trailing end 150 is significantly greater thanthe width and/or height of the ink stick body between the lateral sidesurfaces 140 and the height of the ink stick body between the topsurface and the bottom surface. The longitudinal length of the ink stickbody is typically the dimension that is substantially aligned with thefeed direction of a feed channel. The width and height of the ink stickare perpendicular to the length. The ratio of the length of the inkstick body to the width and/or height may depend on a number of factorssuch as aesthetics, fabrication, loader orientation and/or functionalrequirements. Size and aspect ratio descriptions of the stick and loaderfeed channel used above are useful in visualizing and appreciating thefeatures of the present invention but are not intended to be limitationsto the embodiments incorporating these and related functions.

As mentioned above, the feed path defined by the feed channel mayinclude linear as well as arcuate, or curved sections. In order tofacilitate the movement of longer sticks along the curved portions ofthe feed path, one or more of the leading edges 160, 164, 168, 170and/or trailing edges 174, 178, 180, 184 of an ink stick may beconfigured as clearance edges 200 as shown in FIG. 5. As shown in FIG.6, clearance edges 200 enable ink sticks 100′ to clear the confiningwalls of the feed channel 58 as the ink sticks progress through curvedsections of the feed channel 58 as well as through transition areasbetween linear and curved sections of the feed channel. In oneembodiment, a clearance edge 200 comprises a reduced edge that is angledor shaped to complement the contour of the confining walls in thenon-linear sections of a feed channel. Clearance edges 200 areconfigured to provide spacing between the edges of the ink stick and thewalls of the feed channels as the ink sticks transition into and out ofthe curved sections of the channel. The clearance edge may be a beveledor chamfered edge, a rounded edge, or have any suitable combination ofthese or other contours. The clearance edges on the ink stick enablelonger sticks to pass through a feed channel having linear and curvedsections without drastically reducing the ink volume of the stick. Theclearance edge or chamfer, defined here as an angle, bevel, radius orcontour or combination of such features, is more significant inprominence than a similar feature used in molding, forming, machining orother fabrication artifacts or enablers, such as a drafted surface,deformation or small radius.

The edges of the ink stick that are selected to be treated or contouredto form clearance edges and the degree to which the edges are reduceddepends on the configuration of the ink and feed channel, and, inparticular, the direction of the vector change in the non-linearsections of the channel. For example, in a feed channel that includes atransition from a linear section to a downwardly arced section, such asthe feed channels shown in FIG. 6, clearance edges 200 may be formed atthe leading end 148, the trailing end 150 or both to facilitate forwardand/or reverse feed of the ink sticks between the insertion station andthe melt station. In embodiments of feed channels that includehorizontally curved sections (e.g. curve to the right and/or left), inksticks may include clearance edges at the leading end and/or trailingend adjacent the corresponding side surfaces. Any suitable number ofedges of ink sticks may be configured as clearance edges. For example,ink sticks configured for use in a feed channel having both verticallyand horizontally curved sections may include clearance edges adjacentthe top surface and side surfaces. Clearance edges may be contouredacross the entire width of the edge or only portions of the edge whichhave potential for contact with confining surfaces of the feed channel.Another of the many possible configurations would be an upward inclinewhere the bottom edge of the stick is beveled or shaped to complementthe upward path transition.

In other embodiments, feed channels may be equipped with staticconstraints at one or more strategic positions in the feed channels thatare configured to gently contact, or nudge, ink sticks into optimalalignment or positioning within the feed channel as the ink sticks arefed along the channels. These static constraints, also called nudgers orpositioners, may comprise rollers, ribs, gussets, flexures, rails orsimilar structural forms that may be placed at any suitable position ina feed channel or adjacent a feed path in order to influence alignmentand/or orientation of moving ink sticks. For example, static constraintsmay be placed at the top, bottom, and sides of a feed channel as well asinterfaces between these surfaces, and may be employed at multiplesurfaces in a given area. In addition, multiple static constraints maybe utilized in unison in a feed channel, and each may have the same ordifferent configuration. A proper ink stick progressing in the nominallyideal path of the feed chute need not be position influenced. The staticconstraints that nudge an out of location stick would not typicallycontact the well positioned stick so as to not increase friction orresistance to intended transport. The static constraint or nudgerbenignly acts upon an ink stick when contact is made by a stick thatneeds to be coaxed into a more optimal position to facilitate sensing orto benefit feed progress. The nudger may influence the ink stickposition as it is being inserted and/or at one or more locations as itfeeds along the chute. Transport of the ink from insertion to melt endsof the chute may be facilitated by a conveying or pushing means or bygravity or by any combination of such force inducing methods and themotion enabled by such force influence also enables the ink stickrepositioning function of the nudger. The static constraint may beanchored in location but still be movable, such as with a pivot, flexureor constrained displacement, to aid in nudging the ink stick asintended.

Ink loader geometry may influence the optimal locations for theplacement of static constraints. For example, in a feed channel thatincludes a transition from a linear section to a downwardly arcedsection, nudgers may be positioned near the top surface of the feedchannel where the ink sticks naturally deviate from the straight linepath. Similarly, nudgers may be positioned at the lateral sides of thechannel if the channel curves horizontally to the right or left. Even insituations where the feed channel is substantially straight, ink sticksmay veer from a straight line path due to loader orientation in theimaging device, by feed enhancement or drive features within the loader,by localized thermal influence external to the loader, or by air flow,motion or vibration caused by other working elements within the imagingdevice, many of these influencing a tendency for ink sticks to move outof ideal alignment or position regardless of the loader orientation or afeed path section relative to gravity.

FIG. 7 shows a top view of a portion of a feed channel that includesmultiple nudgers 204 for ensuring that ink sticks are substantiallyaligned to the desired position along a feed path of the feed channel.In this embodiment, two opposing pairs of nudgers 204 are utilized.Although the nudgers are shown in opposing pairs, they might be utilizedon a single side of the feed channel, depending on the movementtendencies of a given feed channel and ink stick configuration. Thedistance between corresponding nudgers on opposing sides of the feedchannel is slightly greater than the width of the ink stick so as toallow passage of ink sticks therebetween. In this embodiment, althoughnot required, the distance between the nudgers that are positioned alongthe same lateral surface is less than the longitudinal length of the inkstick so that the leading end and trailing end of ink sticks may bealigned simultaneously. The nudgers 204 depicted in FIG. 7 compriseramp-like structures that extend from the lateral walls of the feedchannel. Each ramp structure 204 is angled on both sides to provide aguiding surface for gently nudging ink sticks toward the nominal feedpath of the feed channel 58. The ramps may be angled on both sides sothat ink sticks may be moved in either direction along the feed path.Although ramp-like structures are depicted, other configurations ofnudgers may be implemented such as rollers or angled webs or gussets. Inaddition, nudgers may be compliant, flexible, spring loaded or otherwisebiased to lessen the “impact” and/or friction of contact between thenudgers and ink sticks. Nudgers may extend from sides, top, bottom orother surfaces and structures or combinations of such in or about thefeed channel. Pairs of nudgers may be aligned or not aligned at pointsalong the length of the chute at opposite sides where opposite sides maybe left-right, top-bottom and front-back, or any combination thereof,depending on the orientation of the loader.

The configuration of nudgers illustrated in FIG. 7 may be positioned atsubstantially any portion of a feed channel. For example, in oneembodiment, nudgers may be positioned along the feed channel proximatethe insertion station to align and/or orient ink sticks to ensurereliable feed after insertion. Similarly, nudgers may be positionedproximate the melt station to ensure that ink sticks are alignedproperly for contact with an ink melter at the melt station. In anotherembodiment, nudgers may be positioned periodically along the entirelength of the feed path.

Nudgers may also be beneficial in ensuring that encoding features of inksticks are in optimal alignment or position to interact withcorresponding sensors in the feed channel. Referring now to FIG. 8, anembodiment of an ink stick is shown that includes a coded sensor feature220 for encoding variable control information or attribute informationinto the ink stick 100. The coded sensor feature 220 is formed in apredetermined location on the ink stick 100 and is configured to actuateone or more sensors in the feed channel of the ink delivery system.Coded sensor feature 220 may include one or more sensor actuatingelements 224 that may be curved, spherical, angled, square or any shapethat permits reliable sensor actuation, directly or indirectly, such asby moving a flag or actuator or by reflecting or blocking light in anoptical sensing system. The coded sensor feature 220 is shown on theside surface 140 of the ink stick 100 although the coded sensor feature220 may be formed on any surface or more than one surface of the inkstick. The sensor features may be adjacent one another or may be inmultiple locations.

The coded sensor feature 220 of an ink stick is configured to actuatesensors in the feed channel to generate one or more encoded signals thatmay be received by the controller and translated into controlinformation pertaining to the ink stick. The encoded control informationmay be used by a control system in a suitably equipped solid ink jetprinter to control print operations. For example, an imaging devicecontrol system may receive and translate the code word into theappropriate control and/or attribute information pertaining to the inkstick and may then enable or disable operations, optimize operations orinfluence or set operation parameters based on this decoded information.Ink sticks that are not properly aligned and/or oriented as they are fedalong a feed channel may not pass close enough or perhaps may be tooclose to a sensor for proper reading of the coded sensor feature of theink stick. An ink stick may be adjacent at least one sensor when placedin the insertion position where it may then be acted upon by the one ormore sensors. The sensor and/or stick may be in a stationary or movingstate as the ink stick is acted upon or identified by the sensor.

If the coded signal generated by the coded sensor feature indicates thatthe ink stick is compatible or configured for use with the feed channel,normal operations may continue. If the coded signal indicates that theink stick is not configured for use with the feed channel, thecontroller may halt printing operations, issue a control panel messageor other such action. In this case the controller determination of inksuitability may result in any number of responses of the imaging devicesystem, including disabling the transport, moving it for optimal removalor examination of the ink stick, issuing user messages, prompts orwarnings, initiating network communications and so forth. In oneembodiment, the controller may be configured to halt operations when anincompatible, unrecognized or damaged ink stick is detected by disablingthe drive member to ensure that the ink stick is not delivered to themelt plate.

To ensure reliable reading of the coded sensor features of ink sticks,feed channels may include nudgers to act as constraining guides toposition and/orient the ink sticks correctly as they are fed pastcorresponding sensors in the feed channel. FIG. 9 shows an embodiment ofa feed channel 58 that includes a sensor system 230 designed tointerface with the coded sensor feature 220 of the ink stick 100 andnudgers 204 for ensuring the ink sticks are positioned optimally withrespect to the sensors of the sensor system 230. The sensor system 230may include a flag or an optical sensing system configured to detect thecoded sensor feature, and for generating a signal that is output to acontroller 234. The sensor system 230 is positioned along a lateral sideof the feed channel near the bottom of the feed channel. Nudgers 204 arepositioned on opposing sides of the feed channel to control thealignment and/or orientation of the ink stick so that the coded sensorfeature 220 may pass at a desired distance from the sensor system. Inthis embodiment, the nudgers 204 comprise ramp structures similar to theones shown in FIG. 7, although any suitable type of nudger may be used.The nudgers are configured to contact the ink stick gently as it is fedalong the channel to urge the ink stick into a position in which thecoded sensor feature of the ink stick may actuate (or not actuate) thesensor flag. Any suitable number and/or configuration of nudgers may beimplemented. An ink stick ideally positioned as it nears and passes anudger need not actually contact a nudger where its purpose is toposition a stick to a nominal location or path.

Nudgers 204 are generally configured to ensure the reliable feeding andsensing of correctly configured compatible ink sticks in the imagingdevice. As mentioned above, broken ink sticks and/or smaller ink sticksmay not be properly influenced by the static constraints and other feedcontrol protocols that may be incorporated into the feed channel. Ifsmaller ink sticks are inserted that are incompatible with the phasechange ink jet printer in which they are being used or if an ink stickhas broken into pieces, severe jams may occur and considerable errorsand malfunctions may result. Therefore, in addition or as an alternativeto the static constraints described above, feed channels may includestrategic barriers that are configured to prevent the passage ofincorrectly configured ink sticks and to inhibit the passage of brokensections of ink sticks.

Strategic barriers may comprise rollers, gussets, protrusions or similarelements that may be placed as needed in the feed channel to impede thepassage of improperly configured and/or shaped ink sticks. As anexample, FIG. 10 shows an embodiment of a strategic barrier 240 that isincorporated in the insertion area of the feed channel 58 beneath thekeyed opening 60. In this embodiment, the strategic barrier 240comprises at least one protrusion that is positioned adjacent the bottomside surface of the feed channel 58 a short distance behind where thefront, or leading end 148, of a properly configured/shaped ink stickwould come to rest after insertion. As shown in FIG. 10, the leading end148 of ink sticks having the proper length for insertion through thekeyed opening 60 extends beyond the strategic barrier 240 afterinsertion, and, therefore, may not catch on the barrier 240 as the inkstick 100 is moved forward in the feed direction F as shown in FIG. 10.Conversely, as shown in FIG. 11, the leading end 148′ of shorter inksticks or ink stick pieces 100′ may not be guided past the barrier 240after insertion, and, consequently, may be caught on the barrier 240 asthe ink stick 100′ is moved forward thereby preventing passage of inksticks that may not be configured for use with the imaging device.Broken pieces or non-optimized ink stick configurations generally wouldnot feed in an ideal path and when off axis have a higher chance ofbeing obstructed. As shown in FIG. 11, a flexible or movable nudger 206that intrudes somewhat into the ink feed path can be used to nudge anink stick leading end toward a barrier if the stick is too short to beheld to the nominal feed path by other nudgers, guides or feed pathfeatures that would simultaneously act on an appropriate length andshaped ink stick. The movable nudger 206 would be pushed aside by astick being adequately guided or positioned by additional featuresintended to do so, such as multiple or strategically placed nudgers. Thebarrier 240 is not expected to positively inhibit feed of all incorrector broken stick pieces.

Strategic barriers may be placed at any or multiple locations along thefeed path, and may be used in conjunction with static constraints. FIGS.12 and 13 show an embodiment of a feed channel 58 that incorporates bothstatic constraints 204 and strategic barriers 240. In this embodiment, afirst pair 204A of opposing static constraints is positioned near wherethe front, or leading end 148, of a properly configured/shaped ink stick100 comes to rest after insertion, and a second pair 204B of opposingstatic constraints is positioned near where the back, or trailing end,of the properly configured ink stick comes to rest after insertion. Thestrategic barrier 240 is positioned behind the first pair of staticconstraints 204A. The static constraints may comprise rollers, angledgussets, etc. that are configured to maintain an ink stick slightlyinboard of these constraints as the ink stick 100 is moved forward. Asshown in FIG. 13, an ink stick 100 having the proper length forinsertion through the keyed opening 60 may be positioned within thestatic constraints 204 at each end of the ink stick 100. The staticconstraint 204 is configured to extend very near the surface of anideally positioned ink stick supported by a guide, conveyance member orother bottom support feature or surface. The constraint feature(s) wouldnot normally become a support for the ink stick but may on occasioncontribute to support as they engage a stick in a nudging fashion.Strategic barrier feature(s) have a more abrupt, blocking configurationwith respect to interface with an ink stick but would not generallyinfluence a stick in the nominal feed path. Therefore, the strategicbarrier 240 of FIG. 13 is not in a position to impede the passage of aproperly configured ink stick. Ink sticks that do not have the properlength or width are not properly positioned along the nominal feed pathand may gravitate or be directed toward a barrier after insertion.Consequently, the improperly configured ink sticks may be caught on thebarrier as the ink stick is moved forward.

Larger ink sticks such as the ink stick shown in FIG. 3 may be moreprone to breaking into pieces when mishandled or dropped than smallerink sticks. Broken pieces of ink sticks generally may not feed reliably.Therefore, another feature that may be incorporated into ink sticks is abreakage control feature. Referring to FIG. 14, a breakage controlfeature comprises one or more subtle notches 250 or similar featuresplaced at one or more locations on the ink stick 100 that are configuredto control or influence the position where the ink stick breaks whenmishandled. The break location may thus be somewhat predictable eventhough the configuration of break surfaces would varyundeterministically. It is expected that the major broken sections orpieces would be similarly predictable to the extent that the break maytypically result in two pieces as opposed to an unknown several.Breakage control features 250 may be positioned anywhere on the inkstick, but may be beneficially positioned at weak or vulnerablelocations that are most affected by internal fabrication stress or atpoints most complementary to feed control objectives for a particularsystem. This feature 250 facilitates a cleaner break of the ink stick100 into separate ink stick sections 100A, 100B. Thus, breakage controlfeatures 250 enable some predictability of the size of ink stick piecesthat may be inserted into a feed channel so that feed control featuressuch as static constraints and/or strategic barriers may be moreeffective.

FIG. 15 illustrates how the static constraint/strategic barrier systemas depicted in FIG. 13 may be used with an ink stick having a breakagecontrol feature 250. As can be seen, the ink stick is broken at thebreakage control feature into sections 100A and 100B. The ink stick mayhave been broken before or after insertion. In any case, the strategicbarrier 240 is positioned so that it is in front of the breakage controlfeature 250 after the ink stick is inserted. Therefore, the leading end100B of the ink stick, having been controllably separated and of a knownsize, may be allowed to progress through the feed channel 58. The rearportion 100A of the ink stick may be caught by the barrier 240. Althoughnot necessary, a flexible or movable nudger 206 may be used to nudge theleading end of the rear portion 100A of the ink stick toward the barrier240. Reducing the likelihood of the rear broken section to feed forwardalong with the leading section is an aid to preventing the two sectionsfrom creating a wedge at the break interface that would impedepredictable feed performance along some portion of the feed path wherethat location may otherwise be unpredictable.

In another embodiment, static constraints and strategic barriers may beincorporated into a single structure. Such a configuration may bebeneficial at locations where the alignment and/or orientation of inksticks is not fully influenced by the guide/support surfaces or elementsof the feed channel such as in non-linear portions of the feed path.FIG. 16 is a side view of an embodiment of a feed channel 58 thatincludes a transition from a linear section to a downwardly arcedsection. In this embodiment, a barrier/constraint 260 is positioned at apoint R on the top surface of the feed channel which corresponds to thetransition from the linear portion of the channel to the arced portionof the channel. The barrier/constraint of FIG. 16 is configured for usewith an ink stick having a clearance edge, or beveled edge, at theleading edge 148 adjacent the top surface of the ink stick. Thebarrier/constraint 260 comprises a spring loaded roller that isconfigured to lightly push against the clearance edge 200 of the inkstick, allowing it to pass. The clearance edge 200 engages the roller atan angle that allows the barrier/constraint to be moved upward therebycompressing the spring and allowing the barrier/constraint to move overthe top surface of the ink stick. This interface may also beneficiallypush down on the leading edge of the stick to prevent it from hanging upon the general channel upper confines. However, as shown in FIG. 17, inkstick 100′ having an abrupt leading edge 148, such as may be the casewith improperly configured ink sticks and/or ink stick fragments, mayengage the barrier/constraint 260 at an angle that does not allow forupward movement of the barrier/constraint 260 thereby blocking thepassage of a potentially incompatible ink stick. Such sticks or stickpieces become more difficult to remove from the feed channel the furtherthey progress so blockage at this point is more user friendly forretrieval.

Those skilled in the art will recognize that numerous modifications canbe made to the specific implementations described above. Those skilledin the art will recognize that clearance edges, static constraints,and/or strategic barriers may have numerous shapes and configurationsother than those illustrated. Therefore, the following claims are not tobe limited to the specific embodiments illustrated and described above.The claims, as originally presented and as they may be amended,encompass variations, alternatives, modifications, improvements,equivalents, and substantial equivalents of the embodiments andteachings disclosed herein, including those that are presentlyunforeseen or unappreciated, and that, for example, may arise fromapplicants/patentees and others.

1. A system for an ink delivery system of a phase change ink imagingdevice, the system comprising: a feed chute having a first endconfigured to receive a solid ink stick and a second end positionedproximate a melting device to melt the solid ink stick, the feed chutebeing configured to guide at least one solid ink stick from the firstend of the feed chute to the second end of the feed chute; at least onesensor positioned proximate a portion of the feed chute between thefirst end of the feed chute and the second end of the feed chute, the atleast one sensor being configured to detect a coded sensor feature ofthe solid ink stick as the solid ink stick moves from the first end ofthe feed chute to the second end of the feed chute; and at least onenudger positioned between the first end of the feed chute and the secondend of the feed chute, the at least one nudger being configured toorient the solid ink stick to enable the at least one sensor to detectthe coded sensor feature of the solid ink stick at the portion of thefeed chute between the first end of the feed chute and the second end ofthe feed chute.
 2. The system of claim 1, the at least one sensorcomprising at least one mechanically settable flag configured to be setby the coded sensor feature of the solid ink stick in response to thenudger orienting the solid ink stick at the at least one sensor.
 3. Thesystem of claim 1, the at least one sensor comprising an optical sensorconfigured to detecting the coded sensor feature of the solid ink stickoptically.
 4. The system of claim 1, the at least one nudger comprisingat least one pair of nudgers, each nudger in the at least one pair ofnudgers being positioned on opposite sides of the feed chute andextending toward a middle of the feed chute.
 5. The system of claim 3,the at least one nudger comprising a first pair of nudgers and a secondpair of nudgers separated from each other by a longitudinal distancethat is less than a length of the solid ink stick, the first pair ofnudgers and the second pair of nudgers being positioned beneath anopening in the feed chute at the first end of the feed chute to orientthe solid ink stick with reference to an axis of insertion in responseto the solid ink stick being imprecisely inserted through the opening inthe feed chute.
 6. The system of claim 5 further comprising: anobstructor being positioned in the feed chute and extending between thefirst pair of nudgers and the second pair of nudgers, the first pair ofnudgers and the second pair of nudgers being configured to guide inksticks having a length greater than the longitudinal distance separatingthe first pair of nudgers from the second pair of nudgers and theobstructor being configured to block passage of a solid ink stick havinga length less than the longitudinal distance separating the first pairof nudgers from the second pair of nudgers.
 7. The system of claim 6,the obstructor being positioned with reference to a position of abreakage control feature of the solid ink stick, the breakage controlfeature being configured to facilitate breakage of the solid ink stickat a location that produces a leading ink stick piece and a trailing inkstick piece, the obstructor being positioned in the feed chute to blockpassage of a trailing ink stick piece of an ink stick separated at thebreakage control feature in the solid ink stick.
 8. The system of claim1, the at least one nudger comprising a roller.
 9. The system of claim1, the at least one nudger comprising a ramp-like projection.
 10. An inkdelivery system of a phase change ink imaging device, the systemcomprising: a feed chute having a first end configured to receive solidink sticks and a second end positioned proximate a melting deviceconfigured to melt solid ink sticks that travel from the first end ofthe feed chute to the second end of the feed chute, the feed chute beingconfigured to guide solid ink sticks from the first end of the feedchute to the second end of the feed chute; an opening at the first endof the feed chute, the opening being configured to receive ink stickshaving a predetermined length; an obstructor positioned proximate theopening in the first end of the feed chute, the obstructor beingconfigured to block passage of ink sticks having a length less than apredetermined from the opening in the feed chute; and at least one pairof nudgers in the feed chute beneath the opening in the feed chute, theat least one pair of nudgers being configured to position a leading endof a solid ink stick having a length greater than the predeterminedlength beyond the obstructor to enable ink sticks having a lengthgreater than the predetermined length to pass the obstructor and travelalong the feed chute to the second end of the feed chute.
 11. The inkdelivery system of claim 10 further comprising: at least one sensorpositioned between the first end of the feed chute and the second end ofthe feed chute, the at least one sensor being configured to detect acoded sensor feature of the solid ink stick as the solid ink stick movesfrom the first end of the feed chute to the second end of the feed chute12. The ink delivery system of claim 11, the at least one sensorcomprising an optical sensor configured to detect the coded sensorfeature of the solid ink stick optically.
 13. The ink delivery system ofclaim 10, the at least one nudger comprising a roller.
 14. The inkdelivery system of claim 10, the at least one nudger comprising aramp-like projection.